Looks great! Take a look at the thread I just started. BMW posted a sound clip of a 335i with the M Performance exhaust revving, accelerating, and driving by on the BWM.com site. Let us know if this seems like an accurate recording compared to your new exhaust.

I personally believe that the exhaust sounds much better in person than it does in the clip provided on the BMW site. And it sounds pretty good in that clip (notwithstanding the low quality of the audio).